After the annealing of the cornet, i could see some kind of black stain on either side of the parting tray, and even on the thimble. How could i get rid of from the "black stain" and what caused this uneven color on the tray.
After the annealing of the cornet, i could see some kind of black stain on either side of the parting tray, and even on the thimble. How could i get rid of from the "black stain" and what caused this uneven color on the tray.